Window shade systems typically include a pocket (or space) for mounting the shade and another pocket for housing the wiring associated with the shade and other electronics. The window shade installer must often determine where to locate each of the pockets. The locations of the pockets may be important for not only accessibility, but also to comply with certain fire codes. An important part of the decision for the pocket location is the different codes that may apply to different areas. For example, items that exist in a room may be subject to different fire codes than items that exist in the ceiling or plenum. Such codes may determine if the contractor needs to include plenum cable or non-plenum cable. The type of jacket surrounding the cable may be impacted by the location of the cable.
The plenum spaces are between a drop and standard ceiling. The plenum spaces may also similarly exist in the floor space. These spaces are where the air in a building circulates, so these spaces are used to aid in heating and cooling functions. While non-plenum (PVC) cable is less expensive, plenum cable is often required when no conduit is used in the plenum spaces. Fire and smoke travel quickly in plenum spaces. As such, the levels of toxicity in the smoke are typically lower since plenum cable includes a jacket that is often comprised of flame-resistant material (e.g., Teflon). The flame resistant material results in the cable smoking less than regular non-plenum (PVC) cable and the smoke that is emitted is less toxic. If the window shade pocket can be considered to be part of the room (and not part of the plenum), then the less expensive non-plenum cabling can be used in the pocket.
Moreover, a pocket that holds a window shade may be a very long structure. Because different pockets may need to accommodate different size shades, the pockets may vary in size. Furthermore, the pockets may include different features which may need to be incorporated into the pocket walls. The design of a pocket should take into consideration all of these features, while still being designed to be as light and inexpensive as possible.